Hi all, I've reviewed this document as part of the transport area review team's ongoing effort to review key IETF documents. These comments were written primarily for the transport area directors, but are copied to the document's authors for their information and to allow them to address any issues raised. When done at the time of IETF Last Call, the authors should consider this review together with any other last-call comments they receive. Please always CC tsv-art@… if you reply to or forward this review. Summary: This draft is basically ready for publication, but has nits that should be fixed before publication. Editorials: - Abstract says "DISCLAIMER:...": This should be removed before publication or there is an issue with the intended status of Standards Track. - A nit, but: section 7.3.4 uses http instead of https in the example: "instance": "http://example.com/agreement/?token=W8Ih3PswD-8" All other instances use https. Technicals: - Section 8.2. Retrying challenges Any guidance on what "some times" means? At least in terms of a time scale, e.g., seconds, minutes, hours? Thanks for the clearly written document! Regards, Martin Stiemerling